I would anticipate that there are AE Expressions, already written, that would do pretty much what you want to do.

If you have not done so, I would post to the AE forum, and you'll probably get several recs. for similar Expressions, either free ones, or for sale. Also, since you are ending up using this as a DVD Menu, you might want to see this SITE for some tips, and ideas. [Note: looks like Jon's site is down today, but check back.]

I just happened to be leaving another thread, when yours popped up on my screen.

I understand the tedium of doing that sort of thing by hand in PrPro. Most of my animations are simple enough, that I do not use AE as much as I should. For what you describe, I'd be looking for an Expression, or plug-in too!

Give Jon Geddes' site a day, or two, and do have a look. He's the AE to Encore Menu guru on the Encore forum - man, I hope that he's not dumped his site.